Abstract  The use of solid-state fermentation (SFF) of low cost substrates by fungal species to generate organic acid solutions for washing of lead from a contaminated soil was evaluated in this study. SFF filtrates were generated by fermentation of four substrates (corn cobs, apple pomace, rice and hay) with three fungal species (Aspergillus niger NRRL 2001 (A. niger 1), Aspergillus niger ATCC 64065 (A. niger 2), Aspergillus foetidus NRRL 337) at three fermentation times. The concentration and speciation of organic acids of the filtrates was found to be a function of the substrate type, the fungal species and the fermentation time. Fermentation of rice resulted in the highest concentrations of citric acid while fermentation of corn cobs, apple pomace and hay tended to generate oxalic acid with an increasing fraction of this acid as the fermentation progressed. Batch extraction tests that employed the SSF filtrates revealed that soluble lead concentrations as high as 35 mg/l could be achieved. Filtrates containing elevated concentrations of citric acid resulted in the greatest lead extraction while oxalic acid inhibited solubilization. Due to the buffering of pH that was provided by the soil in the batch tests this factor did not appear to influence lead extraction. Lead extraction was observed over an extended period of time in a column test. Lead extraction was strongly influenced by the pH of the soil column and less strongly influenced by the organic acid content of the SSF filtrate. The speciation of organic acids was substantially modified from primarily citric acid in the SSF filtrate to gluconic acid in the soil column discharge.

Abstract  The formation of volatile compounds in fresh cheese by 10 Enterobacteriaceae strains of dairy origin (4 Hafnia alvei, 2 Serratia liquefaciens, 1 Enterobacter cloacae, 1 Enterobacter sakazakii, and 2 Escherichia coli strains) was investigated. Small cheeses were made from pasteurized cow's milk separately inoculated with 1-3 x 10(3) CFU/ml of each of the Enterobacteriaceae strains, with glucono-8-lactone added to achieve a pH value of 5.2 in the curds. All strains reached counts close to 10(8) CFU/g in 1-day-old cheeses and survived well from day 1 to day 8. Cheeses were analyzed for volatile compounds by gas chromatography-mass spectroscopy, after extraction by dynamic headspace using a purge and trap apparatus. Sixty-one volatile compounds were determined in cheeses, 31 of which were further investigated. Significant increases of aldehydes, sulfur compounds, and aromatic compounds were recorded from 2-h curd to 1-day-old cheese, and of ketones, alcohols, and acids from 2-h curd to 8-day-old cheese. Acetaldehyde, 2-methyl propanal, and 3-methyl butanal predominated among aldehydes; 2,3-butanedione, 2,3-pentanedione, and 3-hydroxy 2-butanone among ketones; ethanol, 2-methyl propanol, and 3-methyl butanol among alcohols; and ethyl acetate among esters. Hierarchical cluster analysis of strains using the data of 31 volatile compounds separated clearly the strain of E. sakazakii, which produced high amounts of volatile compounds, from the other Enterobacteriaceae strains.

Abstract  BACKGROUND: Phosphorus deficiency is a major constraint to crop production due to rapid binding of the applied phosphorus into fixed forms not available to the plants. Microbial solubilization of inorganic phosphates has been attributed mainly to the production of organic acids. Phosphate-solubilizing microorganisms enhance plant growth under conditions of poor phosphorus availability by solubilizing insoluble phosphates in the soil. This paper describes the production of organic acids during inorganic phosphate solubilization and influence on plant growth as a function of phosphate solubilization by fluorescent Pseudomonas.

RESULTS: Nineteen phosphate-solubilizing fluorescent Pseudomonas strains of P. fluorescens, P. poae, P. trivialis, and Pseudomonas spp. produced gluconic acid, oxalic acid, 2-ketogluconic acid, lactic acid, succinic acid, formic acid, citric acid and malic acid in the culture filtrates during the solubilization of tricalcium phosphate, Mussoorie rock phosphate, Udaipur rock phosphate and North Carolina rock phosphate. The strains differed quantitatively and qualitatively in the production of organic acids during solubilization of phosphate substrates. Cluster analysis based on organic acid profiling revealed inter-species and intra-species variation in organic acids produced by Pseudomonas strains. The phosphate-solubilizing bacterial treatments P. trivialis BIHB 745, P. trivialis BIHB 747, Pseudomonas sp. BIHB 756 and P. poae BIHB 808 resulted in significantly higher or statistically at par growth and total N, P and K content over single super phosphate treatment in maize. These treatments also significantly affected pH, organic matter, and N, P, and K content of the soil.

CONCLUSION: The results implied that organic acid production by Pseudomonas strains is independent of their genetic relatedness and each strain has its own ability of producing organic acids during the solubilization of inorganic phosphates. Significant difference in plant growth promotion by efficient phosphate-solubilizing Pseudomonas strains point at the need for selecting potential strains in plant growth promotion experiments in conjunction with various phosphate substrates for their targeted application as bioinoculants.

Abstract  A novel and practical glucose biosensor was fabricated with immobilization of Glucose oxidase (GOx) enzyme on the surface of citric acid (CA) assisted cobalt ferrite (CF) magnetic nanoparticles (MNPs). This innovative sensor was constructed with glassy carbon electrode which is represented as (GOx)/CA-CF/(GCE). An explicit high negative zeta potential value (-22.4 mV at pH 7.0) was observed on the surface of CA-CF MNPs. Our sensor works on the principle of detection of H2O2 which is produced by the enzymatic oxidation of glucose to gluconic acid. This sensor has tremendous potential for application in glucose biosensing due to the higher sensitivity 2.5 microA/cm2-mM and substantial increment of the anodic peak current from 0.2 microA to 10.5 microA.

Abstract  Transition metal chalcogenides, especially molybdenum disulfide, have recently got wide attention from researchers because of their unique intrinsic characteristics. However, until now, few literatures have reported the photoluminescent MoS2 materials and their applications. In this work, we reported a bottom up strategy to synthesize water-soluble molybdenum disulfide quantum dots (MoS2 QDs) through a facile hydrothermal route using sodium molybdate and glutathione as Mo and S sources. The obtained MoS2 QDs show blue emission with a high quantum yield (similar to 10.3%) and robust dispersibility and storage stability optical property in aqueous solution. During the experiment, we found that in the presence of hydrogen peroxide (H2O2), the fluorescence of MoS2 QDs is quenched due to the interaction between H2O2 and MoS2 QDs. Simultaneously, glucose oxidase catalyzes the oxidation of glucose to produce gluconic acid and H2O2, so we can use this probe to detect glucose. By reason of the high zymolyte specificity of glucose oxidase, the detection of glucose has good selectivity and sensitivity with a detection limit of 5.16 mu M. Finally, the method is successfully applied for detection of glucose in fetal bovine serum samples. (C) 2017 Published by Elsevier B.V.

Abstract  The preterm infant fed parenterally is prone to some demineralisation due in part to insufficient Calcium (Ca) and Phosphorus (P) retention. In an attempt to augment Ca and P retention, we prepared a standardised parenteral solution containing calcium gluconate and glucose-1-phosphate (Phocytan) as source of phosphorus, yielding a daily supply of 75 mg/kg Ca and 45 mg/kg P. 28 very low birthweight infants were randomly assigned to receive either this solution (high Ca P ; n = 15) or a conventional formulation containing calcium gluconate and potassium mono- and dibasic phosphate delivering 42 mg/kg Ca and 36 mg/kg P daily (low Ca P ; n = 13). In the high Ca P daily retention was respectively 80% and 99% for Ca and P whereas in the low Ca P group, retention was 70% and 82%. Serum parathormone levels were significantly lower in the high Ca P group. We conclude that parenteral nutrition with a new high Ca P supplement results in an augmented Ca and P retention in very low birthweight infants. This may help to prevent neonatal bone demineralization.

Abstract  Due to stricter environmental legislation and implementation of the "waste valorization" concept, recycling of dairy effluent, whey, has drawn a considerable attention. The main constituent of whey is lactose, which is responsible for high biological oxygen demand (BOD) and chemical oxygen demand (COD) values. Therefore, without going to its direct disposal into aquatic system, synthesis of nutraceuticals from lactose is considered a commendable challenge. Lactose-derived nutraceuticals, such as galacto-oligosaccharide (GOS), lactulose, lactitol, lactosucrose, lactobionic acid, gluconic acid, lactone, and tagatose, have been synthesized through different chemical and biochemical reactions, such as hydrolysis, transgalactosylation, oxidation, reduction, isomerization, and hydrogenolysis, considering raw whey or isolated lactose as feedstock. Pure biocatalyst (enzyme) and inorganic catalyst have been used for the synthesis of lactose-based nutraceuticals by different types of operations, such as conventional batch and continuous bioreactors with free catalyst, continuous packed bed bioreactor with immobilized catalyst, moving bed reactor, and membrane-assigned bioreactor. Moreover, in many cases, lactose-based nutraceuticals (lactic acid, lactosucrose, lactobionic acid, gluconic acid, and tagatose) have been synthesized by microbial fermentation process. Free microbial cell in batch and continuous fermentor and whole cell immobilized packed bed bioreactor have been used for this purpose. This review presents and compares different process-related technological aspects for synthesis of lactose-derived nutraceuticals from whey.

Abstract  Molar conductivity of saturated aqueous solutions of calcium d-saccharate, used as a stabilizer of beverages fortified with calcium d-gluconate, increases strongly upon dilution, indicating complex formation between calcium and d-saccharate ions, for which, at 25 °C, Kassoc = 1032 ± 80, ΔHassoc° = −34 ± 6 kJ mol–1, and ΔSassoc° = −55 ± 9 J mol–1 K–1, were determined electrochemically. Calcium d-saccharate is sparingly soluble, with a solubility product, Ksp, of (6.17 ± 0.32) × 10–7 at 25 °C, only moderately increasing with the temperature: ΔHsol° = 48 ± 2 kJ mol–1, and ΔSassoc° = 42 ± 7 J mol–1 K–1. Equilibria in supersaturated solutions of calcium d-saccharate seem only to adjust slowly, as seen from calcium activity measurements in calcium d-saccharate solutions made supersaturated by cooling. Solutions formed by isothermal dissolution of calcium d-gluconate in aqueous potassium d-saccharate becomes spontaneously supersaturated with both d-gluconate and d-saccharate calcium salts, from which only calcium d-saccharate slowly precipitates. Calcium d-saccharate is suggested to act as a stabilizer of supersaturated solutions of other calcium hydroxycarboxylates with endothermic complex formation through a heat-induced shift in calcium complex distribution with slow equilibration upon cooling.

Abstract  Background: In this study, the performance of aerobic batch fermentation with Aspergillus niger producing sodium gluconate under different oxygen supply levels through adjusting the agitation rate were investigated. The response of glucose metabolism in A. niger to different oxygen uptake rate (OUR) levels has been studied in the present work. Results: Metabolic flux analysis demonstrated that the high oxygen supply condition was favorable for cell growth and initial sodium gluconate synthesis during the early fermentation phases. However, during the late stable phase, metabolic flux analysis indicated that a high yield of sodium gluconate production could be achieved at a medium OUR level of 55 2.5 mmol L-1 h(-1) as less flux was required for glucolysis and the TCA cycle. With a two-stage OUR control strategy, the final sodium gluconate yield of the batch fermentation was enhanced and reached 93.7% (mol vs mol), which was higher than those obtained using a high oxygen supply level throughout the whole fermentation process. Conclusions: Metabolic flux analysis was successfully used in the present work, and the two-stage OUR control strategy increased the yield of sodium gluconate production to 93.7%.

Abstract  D-glucosaminic acid (2-amino-2-deoxy-D-gluconic acid), a component of bacterial lipopolysaccharides and a chiral synthon, is easily prepared on a multigram scale by air oxidation of D-glucosamine (2-amino-2-deoxy-D-glucose) catalysed by glucose oxidase.

Abstract  This study reported a high titer gluconic acid fermentation using dry dilute acid pretreated corn stover (DDAP) hydrolysate without detoxification. The selected fermenting strain Aspergillus niger SIIM M276 was capable of inhibitor degradation thus no detoxification on pretreated corn stover was required. Parameters of gluconic acid fermentation in corn stover hydrolysate were optimized in flasks and in fermentors to achieve 76.67 g/L gluconic acid with overall yield of 94.91%. The sodium gluconate obtained from corn stover was used as additive for extending setting time of cement mortar and similar function was obtained with starch based sodium gluconate. This study provided the first high titer gluconic acid production from lignocellulosic feedstock with potential of industrial applications.

Abstract  Thirteen cases of feline primary hyperaldosteronism were diagnosed based on clinical signs, serum biochemistry, plasma aldosterone concentration, adrenal imaging and histopathology of adrenal tissue. Two cases presented with blindness caused by systemic hypertension, whilst the remaining 11 cases showed weakness resulting from hypokalaemic polymyopathy. Elevated concentrations of plasma aldosterone and adrenocortical neoplasia were documented in all cases. Seven cases had adrenal adenomas (unilateral in five and bilateral in two) and six had unilateral adrenal carcinomas. Three cases underwent medical treatment only with amlodipine, spironolactone and potassium gluconate; two cases survived for 304 and 984 days until they were euthanased because of chronic renal failure, whilst the third case was euthanased at 50 days following failure of the owner to medicate the cat. Ten cases underwent surgical adrenalectomy following a successful stabilisation period on medical management. Five cases remain alive at the time of writing with follow-up periods of between 240 and 1803 days. Three cases were euthanased during or immediately following surgery because of surgical-induced haemorrhage. One cat was euthanased 14 days after surgery because of generalised sepsis, whilst the remaining cat was euthanased 1045 days after surgery because of anorexia and the development of a cranial abdominal mass. It is recommended that primary hyperaldosteronism should be considered as a differential diagnosis in middle-aged and older cats with hypokalaemic polymyopathy and/or systemic hypertension and should no longer be considered a rare condition.

Abstract  BACKGROUND: The high level of maternal mortality and morbidity as a result of complications due to childbirth is unacceptable. The impact of quality medicines in the management of these complications cannot be overemphasized. Most of those medicines are sensitive to environmental conditions and must be handled properly. In this study, the quality of oxytocin injection, misoprostol tablets, magnesium sulfate, and calcium gluconate injections was assessed across the six geopolitical zones of Nigeria.

METHOD: Simple, stratified random sampling of health facilities in each of the political zones of Nigeria. Analysis for identification and content of active pharmaceutical ingredient was performed using high-performance liquid chromatography procedures of 159 samples of oxytocin injection and 166 samples of misoprostol tablets. Titrimetric methods were used to analyze 164 samples of magnesium sulfate and 148 samples of calcium gluconate injection. Other tests included sterility, pH measurement, and fill volume.

RESULTS: Samples of these commodities were procured mainly from wholesale and retail pharmacies, where these were readily available, while the federal medical centers reported low availability. Approximately, 74.2% of oxytocin injection samples failed the assay test, with the northeast and southeast zones registering the highest failure rates. Misoprostol tablets recorded a percentage failure of 33.7%. Magnesium sulfate and Calcium gluconate injection samples recorded a failure rate of 6.8% and 2.4%, respectively.

CONCLUSION: The prevalence of particularly of oxytocin and misoprostol commodities was of substandard quality. Strengthening the supply chain of these important medicines is paramount to ensuring their effectiveness in reducing maternal deaths in Nigeria.

Abstract  Background: Aliphatic (poly)hydroxy carboxylic acids [(P)HCA] occur in natural, e.g. soils, and in technical (waste disposal sites, nuclear waste repositories) compartments . Their distribution, mobility and chemical reactivity, e.g. complex formation with metal ions and radionuclides, depend, among others, on their adsorption onto mineral surfaces. Aluminium hydroxides, e.g. gibbsite [α-Al(OH)3], are common constituents of related solid materials and mimic the molecular surface properties of clay minerals. Thus, the study was pursued to characterize the adsorption of glycolic, threonic, tartaric, gluconic, and glucaric acids onto gibbsite over a wide pH and (P)HCA concentration range. To consider specific conditions occurring in radioactive wastes, adsorption applying an artificial cement pore water (pH 13.3) as solution phase was investigated additionally.

Results: The sorption of gluconic acid at pH 4, 7, 9, and 12 was best described by the "two-site" Langmuir isotherm, combining "high affinity" sorption sites (adsorption affinity constants [Formula: see text] > 1 L mmol-1, adsorption capacities < 6.5 mmol kg-1) with "low affinity" sites ([Formula: see text] < 0.1 L mmol-1, adsorption capacities ≥ 19 mmol kg-1). The total adsorption capacities at pH 9 and 12 were roughly tenfold of that at pH 4 and 7. The S-shaped pH sorption edge of gluconic acid was modelled applying a constant capacitance model, considering electrostatic interactions, hydrogen bonding, surface complex formation, and formation of solved polynuclear complexes between Al3+ ions and gluconic acid. A Pearson and Spearman rank correlation between (P)HCA molecular properties and adsorption parameters revealed the high importance of the size and the charge of the adsorbates.

Conclusions: The adsorption behaviour of (P)HCAs is best described by a combination of adsorption properties of carboxylic acids at acidic pH and of polyols at alkaline pH. Depending on the molecular properties of the adsorbates and on pH, electrostatic interactions, hydrogen bonding, and ternary surface complexation contribute in varying degrees to the adsorption process. Linear distribution coefficients Kd between 8.7 and 60.5 L kg-1 (1 mmol L-1 initial PHCA concentration) indicate a considerable mineral surface affinity at very high pH, thus lowering the PHCA fraction available for the complexation of metal ions including radionuclides in solution and their subsequent mobilization.

Abstract  Aromatic precursors are precisely in the skin of grapes and nearby cells, and therefore there is a greater expression of the varietal aromas and aromatic precursors when the wine passes through this skin contact, as well as changes in product color. The aim of this study was to evaluate the physical and chemical characteristics of Chardonnay wine that has gone through different periods of skin contact. Chardonnay grapes, grown in vineyards located in the town of Bage, in Campanha Gaucha, were de-stemmed, crushed and a sulfur dioxide (50 mg/L-1) was addeded. The experimental design was a 4 x 3 factorial of 4 treatments with 3 repetitions: T1, the wine obtained directly from pressing machine; T2, skin contact for 2 days; T3, skin contact for 4 days and T4, skin contact for 6 days. After the end of malolactic fermentation wines went under -2 degrees C for the tartaric stabilization. There were analyzed the variables alcohol, total acidity, volatile acidity, total polyphenols, glycerol, gluconic acid and 420, 520 and 620 colors by infrared spectroscopy method by Fourier transform and the means were compared by 5% Tukey test. There was a significant differencein variables alcohol, volatile acidit, glucanic acid and color index of 420 nm (yellow).

Abstract  The choice for this paper was determine by the necessity to identify some practical and objective ways to evaluate the energetic and effort capacity at sport horses, which serve to measure the period and intensity of training and to appreciate the effects of training over the level of physic preparation.

Biologic material used for researches was represented by 15 sport horses from Dinamo Club-Bucharest, animals which come from the effective of Jegalia and Cislau studs.

The method used for researches consists in transformation of glucose, under glucozo-oxidases action in gluconic acid and oxygenate water.

The blood glucose value, at horses used in complete trial competition, oscillated depending on trial' type and increased obviously after effort. The differences between the glucose values before and after effort were very significant for steeple chase and jumping trials and insignificant for cross country. (C) 2016 Published by Elsevier B.V.

Abstract  Alcohol dehydrogenase D (AdhD) is a monomeric thermostable alcohol dehydrogenase from the aldo-keto reductase (AKR) superfamily of proteins. We have been exploring various strategies of engineering the activity of AdhD so that it could be employed in future biotechnology applications. Driven by insights made in other AKRs, we have made mutations in the cofactor-binding pocket of the enzyme and broadened its cofactor specificity. A pre-steady state kinetic analysis yielded new insights into the conformational behavior of this enzyme. The most active mutant enzyme concomitantly gained activity with a non-native cofactor, nicotinamide mononucleotide, NMN(H), and an enzymatic biofuel cell was demonstrated with this enzyme/cofactor pair. Substrate specificity was altered by grafting loop regions near the active site pocket from a mesostable human aldose reductase (hAR) onto the thermostable AdhD. These moves not only transferred the substrate specificity of hAR but also the cofactor specificity of hAR. We have added alpha-helical appendages to AdhD to enable it to self-assemble into a thermostable catalytic proteinaceous hydrogel. As our understanding of the structure/function relationship in AdhD and other AKRs advances, this ubiquitous protein scaffold could be engineered for a variety of catalytic activities that will be useful for many future applications.

Abstract  Progress in miniature chip-design raises demands for implantable power sources in health care applications such as continuous glucose monitoring of diabetic patients. Pioneered by Adam Heller, miniaturized enzymatic biofuel cells (mBCs) convert blood sugars into electrical energy by employing for example glucose oxidase (GOx) on the anode and bilirubin oxidase on the cathode. To match application demands it is crucial to increase lifetime and power output of mBCs. The power output has been limited by the performance of GOx on the anode. We developed a glucose oxidase detection assay (GODA) as medium-throughput screening system for improving GOx properties by directed protein evolution. GODA is a reaction product detection assay based on coupled enzymatic reactions leading to NADPH formation which is recorded at 340 nm. The main advantage of the assay is that it detects the production of d-gluconolactone instead of the side-product hydrogen peroxide and enables to improve bioelectrochemical properties of GOx. For validating the screening system, a mutagenic library of GOx from Aspergillus niger (EC 1.1.3.4) was generated and screened for improved activity using Saccharomyces cerevisiae as host. Directed evolution resulted in a GOx mutant I115V with 1.4-1.5-fold improved activity for beta-d-glucose (Vmax from 7.94 to 10.81 micromol min(-1) mg(-1); Km approximately 19-21 mM) and oxygen consumption kinetics correlate well [Vmax (O2) from 5.94 to 8.34 micromol min(-1) mg(-1); Km (O2) from 700 to 474 microM]. The developed mutagenic protocol and GODA represent a proof-of-principle that GOx can be evolved by directed evolution in S. cerevisiae for putative use in biofuel cells.

Abstract  This is the first report on the degradation of poly(3-hydroxybutyrate) (PHB), and its copolymers poly(3-hydroxyvalerate) P(3HB-co-10-20% HV) by Nocardiopsis aegyptia, a new species isolated from marine seashore sediments. The strain excreted an extracellular PHB depolymerase and grew efficiently on PHB or its copolymers as the sole carbon sources. The degradation activity was detectable by the formation of a transparent clearing zone around the colony on an agar Petri plate after 25 days, or a clearing depth under the colony in test tubes within 3 weeks. The previous techniques proved that the bacterium was able to assimilate the monomeric components of the shorter alkyl groups of the polymers. Nocardiopsis aegyptia hydrolyzed copolymers 10-20% PHBV more rapidly than the homopolymer PHB. The bacterial degradation of the naturally occurring sheets of poly(3-hydroxybutyrate), and its copolymer poly(3-hydroxybutyrate-co-3-hydroxyvalerate) was observed by scanning electron microscopy (SEM). The samples were degraded at the surface and proceeded to the inner part of the materials. Clear morphological alterations of the polymers were noticed, indicating the degradative capability of the bacterium. Plackett-Burman statistical experimental design has been employed to optimize culture conditions for maximal enzyme activity. The main factors that had significant positive effects on PHB depolymerase activity of Nocardiopsis aegyptia were sodium gluconate, volume of medium/flask and age of inoculum. On the other hand, MgSO4 center dot 7H(2)O, KH2PO4, K2HPO4 and NH4NO3 exhibited negative effects. Under optimized culture conditions, the highest activity (0.664 U/mg protein) was achieved in a medium predicted to be near optimum containing (in g/L): PHB, 0.5; C6H11O7Na, 7.5; MgSO(4)center dot 7H(2)O, 0.35; K2HPO4, 0.35; NH4NO3, 0.5; KH2PO4, 0.35; malt extract, 0.5 and prepared with 50% seawater. The medium was inoculated with 1% (v/v) spore suspension of 7 days old culture. Complete clarity of the medium was achieved after 3 days at 30 degrees C.

Abstract  Sucrose from sugarcane is produced in abundance in Brazil, which provides an opportunity to manufacture other high-value products. Gluconic acid (GA) can be produced by multi-enzyme conversion of sucrose using the enzymes invertase, glucose oxidase, and catalase. In this process, one of the byproducts is fructose, which has many commercial applications. This work concerns the batch mode production of GA in an airlift reactor fed with sucrose as substrate. Evaluation was made of the influence of temperature and pH, as well as the thermal stability of the enzymes. Operational conditions of 40 °C and pH 6.0 were selected, based on the enzymatic activity profiles and the thermal stabilities. Under these conditions, the experimental data could be accurately described by kinetic models. The maximum yield of GA was achieved within 3.8 h, with total conversion of sucrose and glucose and a volumetric productivity of around 7.0 g L(-1) h(-1).

Abstract  Low total blood calcium concentration after calving has been demonstrated to be a risk factor for reduced neutrophil function. The objective of this study was to evaluate whether administration of an injectable calcium supplement product soon after calving increased neutrophil oxidative burst or phagocytosis capacity. Cows (n = 27) from 4 farms were blocked by parity and randomly assigned to receive either calcium gluconate (35% wt/vol) in combination with calcium glucoheptonate (10% wt/vol; Theracalcium, Vétoquinol Canada Inc., Lavaltrie, Quebec, Canada) or a placebo within 12 h after calving and again 24 h later. Each dose of 120 mL was injected subcutaneously over 2 sites. Total serum calcium concentration, neutrophil oxidative burst, and neutrophil phagocytosis capacity were measured from coccygeal blood samples before (time 0) and 72 h after first treatment. There was no difference between treatment groups in lactation number, total calcium concentration, oxidative burst, or phagocytosis at time of enrollment. There was no effect of treatment on oxidative burst or phagocytosis by neutrophils. This preliminary study does not support an effect of supplemental calcium to improve neutrophil oxidative burst or phagocytosis capacity of low-parity parturient cows.

Abstract  Dynamic viscoelasticity studies on gelation of soybean 11S protein by glucono-delta-lactone have been done to analyze the gelation process of tofu. Observed gelation curves at constant temperatures were well approximated by first-order reaction kinetics. The saturated storage modulus depended mainly on the concentration of 11S protein. The saturated modulus was proportional to 3.4th power of 11S concentrations. The rate constant of the gelation increased with increasing gelling temperature and was mainly governed by the concentration of glucono-delta-lactone. The activation energy of the gelation was calculated to be 1.5 x 10(1) kJ/mol from an Arrhenius plot of the rate constants. The latent time at which the shear modulus began to deviate from the baseline became shorter with increasing concentration of glucono-delta-lactone. However, the latent time was not shortened by an increase in protein concentration, in contrast to previous findings for many other protein gels.

Abstract  There is a wide interest in developing management and feeding strategies to stimulate gut development and health in newly-weaned pigs, in order to improve growth performance while minimizing the use of antibiotics and rather expensive feed ingredients, such as milk products. A better understanding of the mechanisms whereby antibiotics influence animal physiology, as well as appropriate use of disease models and in vitro techniques, will lead to the development of alternatives to in-feed antibiotic. Given the considerable advances made in the understanding of intestinal nutrient utilization and metabolism, a complimentary goal in nutrition might be to formulate young pig diets with the specific task of optimizing the growth, function and health of the gut. Important aspects of gut health-promoting pig diets are: reduced content of protein that is fermented in the pigs' gut, minimal buffering capacity, minimal content of anti-nutritional factors, and supply of beneficial compounds such as immunoglobulins. The optimum dietary level and type of fibre will vary with the nature of enteric disease challenges and production objectives. These diet characteristics are influenced by feed ingredient composition and feed processing, including feed fermentation and application of enzymes. A large number of feed additives have been evaluated that are aimed at (1) enhancing the pig's immune response (e.g. immunoglobulin; omega-3 fatty acids, yeast derived beta-glucans), (2) reducing pathogen load in the pig's gut (e.g. organic and inorganic acids, high levels of zinc oxide, essential oils, herbs and spices, some types of prebiotics, bacteriophages, and anti-microbial peptides), (3) stimulate establishment of beneficial gut microbes (probiotics and some types of prebiotics), and (4) stimulate digestive function (e.g. butyric acid, gluconic acid, lactic acid, glutamine, threonine, cysteine, and nucleotides). When manipulating gut microbiota the positive effects of gut health-promoting microbes should be weighed against the increased energy and nutrient costs to support these microbes. In some instances feed additives have been proven effective in vitro but not effective in vivo. The latter applies in particular to essential oils that have strong anti-microbial activity but appear not to be effective in controlling bacterial pathogens when fed to pigs. A combination of different approaches may provide the most effective alternative to in-feed antibiotics. (C) 2010 Elsevier B.V. All rights reserved.

Abstract  The recently described species Acetobacter diazotrophicus isolated from sugar cane roots and stems was found capable of growth at pH 3.0 and showed high nitrogenase activity even at pH 2.5. No growth occurred at pH 7.5. Extracellular oxidation of glucose followed by gluconic acid formation was necessary for initiation of logarithmic growth, which proceeded with N2 as the sole nitrogen source. N2-dependent growth did not occur in N-free liquid medium under air, but starter doses of 0.6 to 1 mM (NH4)2SO4 led to active N2-fixing cultures after 34 h. Nitrogenase activity was only partially inhibited by 20 mM (NH4+)2SO4 and several amino acids showed similar effects. However, NO3- did not inhibit or repress nitrogenase activity.

Abstract  Based on the immobilization enzyme technology and the fluorescence capillary analysis method, the authors have developed a highly sensitive fluorescence reaction system and a novel immobilization multienzyme glucose fluorescence capillary biosensor for determining glucose contents. Reaction principle of the system is that under the catalysis of glucose oxidase (GOD) and horseradish peroxidase (HRP) immobilized on inner surface of a medical capillary, beta-D-glucose reacts with dissolved oxygen to form gluconic acid-delta-lactone and hydrogen peroxide, and then the latter reacts with l-tyrosine to produce a tyrosine dimer, which has maximal excitation and emission wavelengths at 320 nm and 410 nm, respectively. Fluorescence of the dimer is proportional to the concentration of the beta-D-glucose. Optimization conditions suitable for the reaction system and the biosensor were as follows. Concentration of the L-tyrosine used as fluorescence reagent was 0.15 mol L(-1), the active concentrations of the GOD and the HRP for the immobilization were 15 kU L(-1) and 8 kU L(-1), respectively. Consumptions of the sample and reagents in one determination were 5.0 microL and 15 microL, respectively. Quantitative range of the biosensor for the glucose was in the range 1-10 micromol L(-1), its relative standard deviation was less than 4.9%, and its detection limit was 0.62 micromol L(-1). The biosensor's recovery was in the range 96-105%. Results of some serum determined with the biosensor and with a commercial glucose-kit were well coincident to each other. Accordingly, the biosensor can be applied to the determination of serum glucose contents in the diagnosis of diabetes.